As shown in FIG. 7, the right and left sides of a journal portion 100 of a crank shaft are provided with a counterweight 101,102, this journal portion 100 is put in to a bulk portion 103 of a cylinder block and a bearing cap, and a ditch is formed on a plane opposed to the counterweight of the bulk portion 103 (bearing cap), a thrust metal 104 (thrust bearing) is inserted into this ditch, the thrust metal 104 receives axial power.
As shown in FIG. 8 (a), (b), the shape of the thrust metal 104 is semi-circular, and an oil ditch 105 is formed on the outside surface opposed to the counterweight.
A device which installs the above described thrust metal into the journal portion as disclosed in Patent Document 1 is known.
In this device, the thrust metal contained in a magazine is taken out in one piece using a slider, two pieces of thrust metal are installed into a transit head in parallel so that the bearing surface of the thrust metal faces outwards, subsequently, the thrust metal on either side of an imposition head is transferred without changing the direction, the thrust metal is aligned sequentially in a thrust metal ditch by the insertion of the assembling head and the movement in the direction of approach, the ditch is provided on either side of a bearing portion of a cylinder block in which a crank shaft is installed, the thrust metal held by an imposition head is given a rotary motion, and the thrust metal is made to come into the thrust metal ditch.
Also, Patent Document 2 discloses that a ditch, in which a semi-circular thrust metal is mounted, is formed on a bulk portion of a cylinder block, a tang is provided at one end of the thrust metal engaged with the ditch and prevents the thrust metal from interfering with the crank shaft.